ECOLOGY

Question 1

Define eutrophication

Answer 1

Process in which there is an overgrowth of plants and algae in a body of water due to an excess of nutrients in the water

Question 2

Describe the process in which sewage is treated

Answer 2

1. Sewage is drained into settling tanks and sedimentation tanks to allow some of the solid waste to settle before being removed
2. Sewage enters aeration tank, where oxygen and bacteria are added -> bacteria remove phosphates and convert nitrates in the wastewater into nitrogen gas
3. Liquid is filtered and solid contents allowed to settle
4. Sewage water is disinfected to reduce the number of microorganisms in the water before it is discharged into the environment

Question 3

What happens to sludge?

Answer 3

Sludge undergoes bacterial digestion to reduce the amount of organic matter and the number of disease-causing microorganisms present

Question 4

Define bioamplification

Answer 4

Increase in concentration of a substance up a food chain (e.g. mercury, arsenic)

Question 5

Define bioaccumulation

Answer 5

Increase in concentration of a substance, due to absorption from food and the environment, in the body tissues of organisms

e.g. DDTl=